Determination of heavy metals and anthraquinone in black tea

Document Type : Original research paper


1 Department of Basic Sciences, Faculty of Medicine, Abadan University of Medical Sciences, Abadan, Iran

2 Abadan University of Medical Sciences, Abadan, Iran

3 Department of Laboratory Sciences, School of Allied Medical Sciences, Abadan University of Medical Sciences, Abadan, Iran


Introduction: A rapid and simple method was investigated for determining the concentration of some contaminants including heavy metals such as lead (Pb), cadmium(Cd), chromium (Cr), and anthraquinone in black tea samples in Iran.
Methods: Heavy metals such as Pb, Cd, and Cr in tea samples were detected using inductively coupled plasma optical emission spectrometry (ICP-OES) after microwave acid digestion (MAD). The anthraquinone in infusion tea samples was determined via liquid chromatography photodiode array detector after the dispersive liquid-liquid microextraction method (DLLME). 
Results:Recoveries of all the tea samples in heavy metals and anthraquinone were in the range of 75% - 89% and 71%-96, respectively. The results of recoveries are in the range of the Association of Official Analytical Chemists (AOAC) and the European Union. RSD in the MAD and DLLME methods was less than 5%. The mean concentrations of Pb, Cd, Cr, and anthraquinone were 0.724, 0.021, 2.98 ppm, and 2.27 ppb.
Conclusion: Overall our results showed that MAD and DLLME methods could successfully determine the concentration of some contaminants such as Pb, Cd, Cr, and anthraquinone in black tea samples.


Main Subjects

  1. Ostrowska J, Stankiewicz A, Skrzydlewska E. Antioxidative properties of green tea. Bromatol Toxicol Chem. 2001;2:131.
  2. Zhu QY, Hackman RM, Ensunsa JL, Holt RR, Keen CL. Antioxidative activities of oolong tea. Journal of Agricultural and Food Chemistry. 2002;50(23):6929-34.
  3. Chandra S, Gonzalez de Mejia E. Polyphenolic compounds, antioxidant capacity, and quinone reductase activity of an aqueous extract of Ardisia compressa in comparison to mate (Ilex paraguariensis) and green (Camellia sinensis) teas. Journal of agricultural and food chemistry. 2004;52(11):3583-9.
  4. Maron DJ, Lu GP, Cai NS, Wu ZG, Li YH, Chen H, et al. Cholesterol-lowering effect of a theaflavin-enriched green tea extract: a randomized controlled trial. Archives of internal medicine. 2003;163(12):1448-53.
  5. Hasegawa R, Chujo T, Sai-Kato K, Umemura T, Tanimura A, Kurokawa Y. Preventive effects of green tea against liver oxidative DNA damage and hepatotoxicity in rats treated with 2-nitropropane. Food and chemical toxicology. 1995;33(11):961-70.
  6. Fujiki H. Green tea: Health benefits as cancer preventive for humans. The Chemical Record. 2005;5(3):119-32.
  7. Bettuzzi S BM, Rizzi F, Castagnetti G, Peracchia G, Corti A. Chemoprevention of human prostate cancer by oral administration of green tea catechins in volunteers with high-grade prostate intraepithelial neoplasia: a preliminary report from a one-year proof-of-principle study. Cancer Res. 2006;66(2):1234-1240. doi:10.1158/0008-5472.CAN[1]05-1145.
  8. Davis AC, Wu P, Zhang X, Hou X, Jones BT. Determination of cadmium in biological samples. Applied Spectroscopy Reviews. 2006;41(1):35-75.
  9. Program NT. NTP toxicology and carcinogenesis studies of EMODIN (CAS NO. 518-82-1) Feed Studies in F344/N Rats and B6C3F1 Mice. National Toxicology Program technical report series. 2001;493:1.
  10. Yusiasih R, Pitoi MM, Ariyani M, Koesmawati TA, Maulana H. Anthraquinone in Indonesian infusion tea: analysis by HPLC–UV and risk assessment. Chemical and Biological Technologies in Agriculture. 2019;6(1):19.
  11. Wang X, Zhou L, Luo F, Zhang X, Sun H, Yang M, et al. 9, 10-Anthraquinone deposit in tea plantation might be one of the reasons for contamination in tea. Food chemistry. 2018;244:254-9.
  12. Hayward DG, Wong JW, Park HY. Determinations for pesticides on Black, Green, Oolong, and White Teas by gas chromatography triple-quadrupole mass spectrometry. Journal of agricultural and food chemistry. 2015;63(37):8116-24.
  13. 2006. BHAUNLoM.
  14. Salahinejad M, Aflaki F. Toxic and essential mineral elements content of black tea leaves and their tea infusions consumed in Iran. Biological trace element research. 2010;134(1):109-17.
  15. F Ap. : guidelines for Standard METHOD performance requirements OMoAoA.
  16. 2010. EGdopram.
  17. Al-Othman ZA, Yilmaz E, Sumayli HM, Soylak M. Evaluation of trace metals in tea samples from Jeddah and Jazan, Saudi Arabia by atomic absorption spectrometry. Bulletin of environmental contamination and toxicology 2012;89(6):1216-9.
  18. Tokalıoğlu Ş, Kartal Ş. Bioavailability of soil‐extractable metals to tea plant by BCR sequential extraction procedure. Instrumentation Science & Technology. 2004;32(4):387- 400.

19 . Natesan S, Ranganathan V. Content of various elements in different parts of the tea plant and in infusions of black tea from southern India. Journal of the Science of Food and Agriculture. 1990;51(1):125-39.

  1. Shokrzadeh M, Saberyan M, Saeedi Saravi S. Assessment of lead (Pb) and cadmium (Cd) in 10 samples of Iranian and foreign consumed tea leaves and dissolved beverages. Toxicological and Environmental Chemistry. 2008;90(5):879-83.
  2. Zazouli MA, Bandpei AM, Maleki A, Saberian M, Izanloo H. Determination of cadmium and lead contents in black tea and tea liquor from Iran. Asian Journal of Chemistry. 2010;22(2):1387.
  3. Karak T, Bhagat R. Trace elements in tea leaves, made tea and tea infusion: A review. Food Research International. 2010;43(9):2234-52.
  4. Mandiwana KL, Panichev N, Panicheva S. Determination of chromium (VI) in black, green and herbal teas. Food Chemistry. 2011;129(4):1839-43.
  5. Marcos A, Fisher A, Rea G, Hill SJ. Preliminary study using trace element concentrations and a chemometrics approach to determine the geographical origin of tea. Journal of Analytical Atomic Spectrometry. 1998;13(6):521-5.
  6. S. Sreenivasan NM NNMaRSFC, 746 2008.
  7. Kasrai M, Shoushtarian M, Bozorgzadeh M. Determination of trace elements in tea leaves by neutron activation analysis. Journal of Radioanalytical and Nuclear Chemistry. 1977;41(1-2):73-9.
  8. Srividhya B, Subramanian R, Raj V. Determination of lead, manganese, copper, zinc, cadmium, nickel and chromium in tea leaves. Int J Pharm Pharm Sci. 2011;13:257-8.
  9. De Meeus C, Eduljee G, Hutton M. Assessment and management of risks arising from exposure to cadmium in fertilisers. I. Science of the total Environment. 2002;291(1- 3):167-87.
  10. Shen F-M, Chen H-W. Element composition of tea leaves and tea infusions and its impact on health. Bulletin of Environmental Contamination and Toxicology. 2008;80(3):300-4.
  11. Dybczynski R, Danko B, Kulisa K, Chajduk-Maleszewska E, Polkowska-Motrenko H, Samczynski Z, et al. Final certification of two new reference materials for inorganic trace analysis. Chemia analityczna. 2004;49(2):143.
  12. Chajduk E. Elemental analysis of black and green tea leaves by instrumental neutron activation analysis. Chemia Analityczna. 2009;54(5):841.
  13. Zhong W-S, Ren T, Zhao L-J. Determination of Pb (Lead), Cd (Cadmium), Cr (Chromium), Cu (Copper), and Ni (Nickel) in Chinese tea with high-resolution continuum source graphite furnace atomic absorption spectrometry. Journal of food and drug analysis. 2016;24(1):46-55